Blood perfusion of teat tissue in dairy cows: Changes associated with pre-milking stimulation and machine milking

Abstract

Mechanical forces during machine milking of dairy cows evoke circulatory impairment of the teat tissue that may affect the teats' defense mechanisms against mastitis pathogens. Ample research describes dimensional changes of different teat traits after machine milking, whereas reports that describe changes in blood circulation of dairy cows' teats are limited. Therefore, the objectives of this study were to (1) describe changes in teat blood circulation that occur after pre-milking teat stimulation and machine milking and (2) study the effect of 2 different milking liners on machine milkinginduced changes in teat blood flow. In a randomized trial, Holstein dairy cows were stratified by parity, stage of lactation, and average daily milk yield during the previous week, and allocated to 1 of 2 treatment groups. Treatment consisted of 1 milking observation with either a round or multisided concave milking liner. Teat scans were taken of the left front and the right hind teats using power Doppler ultrasonography. Imaging occurred before pre-milking udder preparation (T1), after completion of pre-milking udder preparation but before milking-unit attachment (T2), and immediately after unit detachment (T3). Perfusion intensity measurements from teat scans were performed with a commercially available software program. Data from 109 cows were analyzed. A general linear mixed model showed differences in perfusion intensity between time points. Least squares means (95% confidence intervals) for T1, T2, and T3, respectively, were 0.

Measuring oxygen saturation and pulse rate in dairy cows before and after machine milking using a low-cost pulse oximeter

“…Changes of teat skin blood flow dependent on the milking machine settings were reported earlier also by Hamann et al (1994). More recently, Wieland et al (2020), in a study aimed to describe machine milking-induced changes in teat blood circulation of dairy cows, found that blood perfusion intensity of teats decreased after machine milking, compared with the value measured after pre-milking udder stimulation. The Authors attributed the circulatory impairment of the teat to vacuum-induced mechanical forces during machine milking.…”

“…Recently, Wieland et al (2020) have studied the changes induced by machine milking in blood circulation in the teats using power Doppler sonography on 109 Holstein dairy cows. The authors observed that blood flow increased after pre-milking udder preparation, but decreased immediately after the unit detachment probably due to the mechanical stress caused by the milking machine on teat-end tissues.…”

Complex Relationships between Milking-Induced Changes in Teat Structures and Their Pre-Milking Dimensions in Holstein Cows

“…Therefore, an increase in WALL% could allow for improved circulation of fluids within the teat, resulting in an overall reduction of BARREL%. Wieland et al [ 27 ] found that teat blood circulation increased after pre-milking teat stimulation and decreased after machine milking. However, the after-milking value was still higher than before stimulation.…”

Relationship Between Blood Calcium Level and Post-milking Teat Canal Closure in Dairy Cows

“…At the 30th minute post-milking, TCL in NC cows was signi cantly close to the pre-milking state (P < 0.01) compared to SCH cows, and there was a signi cant correlational relationship between ΔTCL30-15 and blood calcium level. This situation suggests the vacuum effect created by the milking system at the 15th minute may suppress the sphincter muscle rhythmic contractions surrounding the teat canal (Paulrud, 2005;Witzel, 1965), or the inability of muscles to perform their normal functions may be caused by acute congestion and edema in the region (Hamann et al, 1994b;Wieland et al, 2020). Therefore, it can be concluded that due to the adverse effects of the milking system, the blood calcium level could not affect the TCL at the 15th minute after milking.…”